Remember dittoes? In schools across the country, there isn't much in the way of "take one, pass it down" anymore. Paper and pen are being upgraded to mouse and keyboard. Classrooms full of computers (never mind cellphones, PDAs, and iPods) present special problems and opportunities for teachers. And according to The New York Times, teachers are learning to fight fire (wire) with fire. Network software NetOp allows teachers to freeze student's desktops during instruction and watch what each student is up to during work time. Other teachers employ high-tech gadgetry to wow students into paying attention. The PC-projected lesson is replacing the chalk board and instead of chalk, teachers are using wirelss keyboards and mouses, typing up pop quizzes on screen which students respond to via remote controls. But before you think everything's gone Jetsons on us, a lot of today's gadgets are only modifying, not replacing, old-time teaching methods. During physics demonstrations, one MIT professor keeps his students awake by "accidently" blowing up a capacitor. "You have to make loud noises once or twice to snap them back to attention," he said.